This invention relates to a method of activating an oxygen concentration cell and the oxygen concentration cell produced.
Generally, an oxygen concentration cell includes a vessel made of a solid electrolyte which is a specific ceramic material having oxygen-ion conductivity, and it detects the oxygen concentration of a gas portion to be measured by measuring electromotive force generated by the difference of an oxygen partial pressure between the gas portion to be measured and a reference gas portion. The oxygen concentration cell may be divided roughly into the following two groups; as the reference oxygen partial pressure source, one using the oxygen in the air and the other using an equilibrium oxygen partial pressure between a metal and an oxide of the metal.
The conventional oxygen concentration cell of the latter type using a metal and its oxide for a solid pole as the reference oxygen partial pressure source has the drawbacks of inferior low temperature performance and poor load characteristics because the internal impedance of the cell is high at the initial stage. When the oxygen concentration cell is connected to a system, the cell is under the same condition as if it were wired to a load resistor when viewed from the side of the cell. For this reason, a voltage detected from the oxygen concentration cell drops. Especially when the oxygen concentration cell is used in the low temperature range, a drastic voltage drop occurs, thereby prohibiting the action of the system as whole. In other words, when a load is wired to the oxygen concentration cell, the terminal voltage of the cell is directly associated with its internal impedance.